Felly sgrifennodd John Hall :
The wet-bulb temperature shows the effect of evaporative cooling on a
wet surface, so the lower the humidity the greater the difference
between dry and wet-bulb temperatures. At 100% relative humidity they
will read the same. Note that if the wet-bulb temperature is below zero
then frost or snow won't melt, even if the dry-bulb temperature is above
zero.

There's also the dewpoint, which also is an indicator of how dry the air
is, as it's the temperature to which the air would need to be cooled for
the relative humidity to reach 100%.

What's the difference between wet bulb and dewpoint? Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Adrian

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais uk

Felly sgrifennodd John Hall :
The wet-bulb temperature shows the effect of evaporative cooling on a
wet surface, so the lower the humidity the greater the difference
between dry and wet-bulb temperatures. At 100% relative humidity they
will read the same. Note that if the wet-bulb temperature is below zero
then frost or snow won't melt, even if the dry-bulb temperature is above
zero.

There's also the dewpoint, which also is an indicator of how dry the air
is, as it's the temperature to which the air would need to be cooled for
the relative humidity to reach 100%.

What's the difference between wet bulb and dewpoint? Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Adrian

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais uk

Felly sgrifennodd John Hall :
The wet-bulb temperature shows the effect of evaporative cooling on a
wet surface, so the lower the humidity the greater the difference
between dry and wet-bulb temperatures. At 100% relative humidity they
will read the same. Note that if the wet-bulb temperature is below zero
then frost or snow won't melt, even if the dry-bulb temperature is above
zero.

There's also the dewpoint, which also is an indicator of how dry the air
is, as it's the temperature to which the air would need to be cooled for
the relative humidity to reach 100%.

What's the difference between wet bulb and dewpoint? Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Adrian

--
Adrian Shaw ais@
Adran Cyfrifiadureg, Prifysgol Cymru, aber.
Aberystwyth, Ceredigion, Cymru ac.
http://users.aber.ac.uk/ais uk

"Adrian D. Shaw" wrote in message
...

What's the difference between wet bulb and dewpoint? Dewpoint can
clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description
above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Try ....

http://www.faqs.org/faqs/meteorology/temp-dewpoint/

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

"Adrian D. Shaw" wrote in message
...

What's the difference between wet bulb and dewpoint? Dewpoint can
clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description
above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Try ....

http://www.faqs.org/faqs/meteorology/temp-dewpoint/

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

"Adrian D. Shaw" wrote in message
...

What's the difference between wet bulb and dewpoint? Dewpoint can
clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description
above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Try ....

http://www.faqs.org/faqs/meteorology/temp-dewpoint/

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

"Adrian D. Shaw" wrote in message
...

What's the difference between wet bulb and dewpoint? Dewpoint can
clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description
above
suggests it can be (so why would people bother measuring it?).

From your description above, there's not any obvious difference.

Try ....

http://www.faqs.org/faqs/meteorology/temp-dewpoint/

Martin.


--
FAQ & Glossary for uk.sci.weather at:-
http://homepage.ntlworld.com/booty.weather/uswfaqfr.htm

In article ,
Adrian D. Shaw writes:
What's the difference between wet bulb and dewpoint?

Dewpoint is the temperature to which the air would have to be cooled to
become saturated, i.e. to have a relative humidity of 100%. Wet bulb
measures the degree of evaporative cooling, so that the lower the
relative humidity the greater the depression of the wet bulb reading
compared to dry bulb. At 100% RH, the dry bulb, wet bulb and dewpoint
will all be the same. For any lower RH, DB WB and, I think, WB DP.

Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

I think the attraction of wet bulb temperature is that it can be
measured directly, by having a thermometer whose bulb is encased in wet
muslin, or some similar device, rather than needing to be calculated.
Once you've measured dry and wet bulb temperatures, then you can use
them to calculate the relative humidity and the dewpoint. Your modern
weather station may be able to measure the humidity directly, but I
don't think that "traditional" simple met instruments could do this, so
observers would derive the humidity from the wet bulb reading rather
than vice versa.
--
John Hall
Johnson: "Well, we had a good talk."
Boswell: "Yes, Sir, you tossed and gored several persons."
Dr Samuel Johnson (1709-84); James Boswell (1740-95)

In article ,
Adrian D. Shaw writes:
What's the difference between wet bulb and dewpoint?

Dewpoint is the temperature to which the air would have to be cooled to
become saturated, i.e. to have a relative humidity of 100%. Wet bulb
measures the degree of evaporative cooling, so that the lower the
relative humidity the greater the depression of the wet bulb reading
compared to dry bulb. At 100% RH, the dry bulb, wet bulb and dewpoint
will all be the same. For any lower RH, DB WB and, I think, WB DP.

Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

I think the attraction of wet bulb temperature is that it can be
measured directly, by having a thermometer whose bulb is encased in wet
muslin, or some similar device, rather than needing to be calculated.
Once you've measured dry and wet bulb temperatures, then you can use
them to calculate the relative humidity and the dewpoint. Your modern
weather station may be able to measure the humidity directly, but I
don't think that "traditional" simple met instruments could do this, so
observers would derive the humidity from the wet bulb reading rather
than vice versa.
--
John Hall
Johnson: "Well, we had a good talk."
Boswell: "Yes, Sir, you tossed and gored several persons."
Dr Samuel Johnson (1709-84); James Boswell (1740-95)

In article ,
Adrian D. Shaw writes:
What's the difference between wet bulb and dewpoint?

Dewpoint is the temperature to which the air would have to be cooled to
become saturated, i.e. to have a relative humidity of 100%. Wet bulb
measures the degree of evaporative cooling, so that the lower the
relative humidity the greater the depression of the wet bulb reading
compared to dry bulb. At 100% RH, the dry bulb, wet bulb and dewpoint
will all be the same. For any lower RH, DB WB and, I think, WB DP.

Dewpoint can clearly
be calculated if you know temperature and humidity (well, my weather
station does it), but can wet bulb be calculated? Your description above
suggests it can be (so why would people bother measuring it?).

I think the attraction of wet bulb temperature is that it can be
measured directly, by having a thermometer whose bulb is encased in wet
muslin, or some similar device, rather than needing to be calculated.
Once you've measured dry and wet bulb temperatures, then you can use
them to calculate the relative humidity and the dewpoint. Your modern
weather station may be able to measure the humidity directly, but I
don't think that "traditional" simple met instruments could do this, so
observers would derive the humidity from the wet bulb reading rather
than vice versa.
--
John Hall
Johnson: "Well, we had a good talk."
Boswell: "Yes, Sir, you tossed and gored several persons."
Dr Samuel Johnson (1709-84); James Boswell (1740-95)